Carburetor governor



Feb. 20, 1962 R. J. BRUNNER CARBURETOR GOVERNOR Filed OCC. 25, 1957 3 Sheets-Sheet 1 INVENTOR.

A TTORNE Y Feb. 20, 1962 R, 1 BRUNNER 3,021,827

CARBURETOR GOVERNOR Filed Oct. 23, 1957 5 Sheets-Sheet 2 IN VEN TOR.

A TTOPNE Y Feb. 20, 1962 R. J. BRUNNER 3,021,827

CARBURETOR GOVERNOR Filed 00TH 25, 1957 3 Sheets-Sheet 5 IN VEN TOR.

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A TTOPNE Y The present invention relates to a charge forming device for an internal combustion engine in which governing means is provided for preventing excessive engine speeds. More specilically, this invention relates to a governing mechanism for a compound type carburetor, e.g. a carburetor having a plurality of induction passages and in which there is a correlation in the actuation of the throttle valves controlling the ow of combustible charge through the respective induction passages.

While governing mechanisms utilized in conjunction with carburetors Iare well known, it has proved particularly difficult to provide satisfactory governing mechanisms for controlling sequentially operating throttle valves in dierent induction passages. In compound type carburetors it is common to have at least one primary throttle and one secondary throttle fand further which throttles are adapted to operate in sequence with the secondary throttle opening only after -a predetermined amount of opening of the primary throttle.

The sequential operation of the throttles of a compound type carburetor may either be achieved mechanically by a mechanism of the type shown in Olson et al. 2,771,282 or automatically through a power servo mechanisms as shown in Braun 2,705,942. Each of the mechanisms for controlling sequential throttles presents its own diiiiculty. Copending application Serial No. 616,529, now Patent No. 2,862,487, granted December 2, 1958, discloses a governing mechanism for controlling mechanically coupled sequentially operating throttles of the type shown in the aforenoted Olson et al. patent.

The present invention is directed to a governing mechanism particularly adapted for use with a compound type carburetor employing la power actuated secondary throttle as illustrated in the Braun patent.

In the present device a carburetor is provided having primary and secondary induction passages which include throttle valves respectively disposed therein. The primary throttle is adapted to be opened in accordance with operator demand as manifested by accelerator pedal position. In addition, however, a governing device is connected to the primary throttle which permits the latter to be closed in the event engine speed exceeds `a given value. A servo mechanism is connected to the secondary throttle and which servo mechanism is interconnected with the primary induction passage so that Ithe actuation ofthe secondary throttle is determined by the air flow `through the primary induction passage. increases beyond a desired value the governing mechanism is adapted to move the primary throttle in a ciosing direction which tends to reduce the air flow through the primary induction passage and in this way modiiies the force tending to open the secondary throttle. It has, however, been found to be inadequate to govern the secondary throttle by modifying the force created by primary induction passage air flow to the extent this occurs in simply closing the prim-ary throttle. It is found that by controlling the secondary throttle actuating vacuum 'force by primary throttle actuation alone causes the secanism is controlled by the governing deyicein such a Thus, as the engine speed r way that when the speed of the engine exceeds a desired value atmospheric pressure is admitted to the secondary throttle servo causing that throttle to be moved to a closed position and avoiding indiscriminate hunting.

Other objects and advantages of the present invention will be apparent from a perusal of the detailed description which follows.

In the drawings:

FIGURE l is a partially sectioned View through a carburetor embcding the present invention;

FIGURE 2 is a partially `sectioned view through the carburetor throttle body showing the throttle actuating mechanisms;

FIGURE 3 is a view along line 3-3 of FIGURE 2; and

FIGURE 4 is a diagrammatic representation of the governing mechanism utilized in the present system.

Referring to the drawings, a compound type carburetor is shown generally at 10. Carburetor 10 may be of the type shown in Patent Number 2,771,282 Oison et al. or any other Well known type. The carburetor will be described in detail only insofar nas is necessary to a proper understanding of the present invention.

Carburetor 10 includes primary and secondary induction passages 12 and 14 having Venturi portions 16 and 18. As best seen in FIGURES l and 2, a lever 20 is connected to the primary throttle shaft 22. In order that a governing mechanism may be utilized in conjunction with the primary throttle 24, a spring 26 is lixed to one end of lever 20 so as to normally urge the throttle in yan open direction. The opening movement of the primary throttle 24 is opposed or limited by an accelerator controlled lever 2S which includes a stop portion 30. As best seen in FIGURES 2 and 3 the adjustable stop 30 is adapted to coact with a corresponding stop member 32 formed on a lever 34 secured to the opposite end of primary thro-tile shaft 22. Thus while spring 26 urges the primary throttle in an open direction, the extent to which such opening may take place is limited by the accelerator controlled stop 3G. In this way it may be seen that the primary throttle may be closed by a governing mechanism against the force of spring 26 without having to work against the force applied by the pressure exerted by the operators foot.

A link or control rod 3S is lixed to the other end of primary throttle lever Zit and is adapted to be actuated by a servo device indicated generally at 40. Servo device 40 includes a pair of casing members i2 and 44 which peripherally clamp a diaphragm member 46 therebetween. Diaphragm 46 includes a rod member 48 centrally iixed thereto and which member is articulated to control rod 38.

Casing 42 and diaphragm i6 form a chamber 59 which is suitably vented to the atmosphere. Diaphragm 46' and casing 44 form a chamber 52 adapted to be suppiied with a vacuum force from a governing mechanism 5d which will be subsequently described. It is apparent that when the governo-r vacuum force reaches a given value it will overcome the throttle opening force of spring 26 yand move the primary thro-ttles 2d- -toward fa closed position.

A lever S6 is fixed -to the secondary throttle shaft 53 and has a control rod or link 60 articulated thereto. The

other end of control rod 6h is articulated to a stud 62 centrally xed to a diaphragm 64 of a secondary throttle actuating servo indicated generally at 66. Servo 66 includes a pair of casing members 68 and "70 adapted to peripherally clamp lthe diaphgarm 64 therebetween. The chamber 72 defined by diaphragm 64 and casing y70 is open to the atmosphere. Chamber 74 detined by diaphragm 64 and cas-ing 68 communicates through a conduit 76 with venturi 16 of the primary induction passage 12. A spring member 78 is disposed within chamber 74 and is adapted to bias the diaphragm 64 and stud 62. in a direction tending to close the secondary throttle Sil.

After the primary throttle has reached a given degree of opening the air flow through primary venturi ld will reach a sufficient value to create a vacuum force in conduit '75 which will overcome the spring 7 and move the iaphragm 64 to the left tending to open the secondary throttle 89 with a torce which will be proportional to the velocity of primary induction passage air flow. The advantage of such a power actuated secondary throttle is that the degree of secondary throttle opening is not determined by operator demand but by engine demand. In other words, with mechanically coupled primary and secondary throttles it is possible for theV secondary throttle to be opened in advance of the actual needs of the engine whereas with the subiect device it is the engines cotosumption of air which determines when the secondary induction passage will supply the additional air required for proper operation of the engine. Y

Insofar as the governing action of the primary throttles 24 is concerned, it is the same as that described in copending application SN. 616,529 Olson, tiled October 17, 1956. lt is the governing of the secondary throttle that differs from the atorenoted copending application. Referring to governor servo 4t?, servo chamber 5?; is communicated through a passage 82 and a conduit S4 to the carburetor induction passage posteriorly of the throttles so as to convey manifold vacuum to the chamber to assist in moving the diaphragm 46 in a throttle` closing direction.

The speed responsive or governor mechanism 54 may be of the type shown and described in Patent 2,664,867 Hartzell et al., tiled February 14, 1951, and does not, per se, constitute a part of the present invention. The speed responsive mechanism is pertinent to the subject invention only in combination with the' subiect unique throttle controlling devices. insofar as the present invention is concerned it will suce to say of the speed responsive device 54 that it includes a shaft 96 driven at engine speed through a gear 92 connected in turn with a member 94 on the engine cam shaft. Radially mounted on the shaft 99 is a centrifugal valve mechanism 96 biased by spring 93 in a position permitting spindle lil@ to uncover port itl?, admitting atmospheric air from an air cleaner conduit ldd to a passage 1% formed in shaft 9G. Passage 196 in turn communicates at its other end with an annular chamber S in registry with a passage liti connecting with conduit 112 communicating with the servo casing d4.

Thus, as long as engine speed remains below a value which will permit safe operation of the engine, valve 96 continues to bleed atmospheric air Vto the servo chamber 52 precluding manifold vacuum from having any eiect on the throttle actuating mechanism. When the engine exceeds a given value, centrifugal weight lll-t shifts the spindle iiil to close port MBZ shutting oi the atmospheric bleed causing manifold vacuum to build up in chamber 52 and to move the diaphragm 46 to the right closing the primaryl throttles 2d.

While the moving of the primary throttles 24 toward a closed position tends to reduce the venturi vacuum torce in conduit 7d, this action has not proven to be positive enough with a hunting action ot the secondary throttle resulting. it has been found necessary to provide an additional device to render the governingV of the secondary throttle more delinite than is otherwise achievable with a power.v actuated secondary throttle.

To this end, a venting device indicated generally at l?. is provided and communicates through a passage 122 with venturi vacuum conduit 76. Passage. @2 includes. a vent port 124 open'to the atmosphere. Passage 12.2 is enlarged to provide a bore 26 in which a needle valve 123 is slidably disposed. The tapered end of needle valve 128 is adapted to coact with passage 122 to control the admission ot atmospheric pressure into vacuum conduit 76.

The actuation of the needle valve 12d is under the controll of a servo mechanism vwhich includes apa/ir' of'casing members 13% and 132 peripherally clamping a diaphragm member 34 therebetween. Casing 32 includes a recess valve 12S to the left tol block the passage 3.22 against the bleeding of atmospheric air thereiuto under normal operating conditions.

The chamber 14u defined by casing 13) and diaphragm 134 communicates With the atmosphere through atmospheric port lift. Chamber 142 defined by casing 32 and diaphragm 134 communicates through a passage i454 with a conduit Md. Conduit 146 communicates at its other end with chamber 52 of servo 4t). Thus chamber 42 is subjected to the same vacuum control forces as is chamber S2 of servo 46'. An orilice R43 is provided in conduit ll in. order to control the rate of actuation of diaphragm 134. When, as already described in relation to servo 46, the engine speed reaches a suhiciently high value to block ott the bleed of atmospheric air through conduit 112 into servo chamber 52, manifold vacuum will act through conduit 146 on diaphragm i314 opening needle valve 128 and venting conduit 7d to atmosphere. A Accordingly, the vacuum force acting on secondary throttle servo 66 is eliminated permittingk spring 78 to move the secondary throttles S6 toward a closed position. In this way when the engine is tending to overspeed the secondary throttle will be automatically closed without any tendency for the latter to hunt as has been experienced with previous systems. v

The carburetor governing system as shown and described is illustrative of the' inventive concept involved. It is possible to make various structural modifications in the mechanisms depicted without departing from the scope of the invention as is set forth in the hereinafter appended claims. Y

I claim:

1. A charge forming device for an internal combustion engine comprising primary and secondary induction passages, a throttle valve in each of said passages, means for opening the primary throttle valve, a servomechanism operatively connected to the secondary throttle valve, said mechanism including a member biasing the secondary throttle in a closing direction, vacuum conduit means communicating the servo mechanism with the primary induction passage to control the operation of the secondary throttle in' accordance with the air flow through the primary induction passage, a governor device, means operatively interconnecting said governor device and the primary throttle valve, said device being adapted to move the primary throttle valve in a closed direction and in so doing to reduce the vacuum in said conduit means, and venting means coacting with said vacuum conduit, said governor device being adapted to actuatey the venting means to admit atmospheric pressure to the vacuum conduit permitting the biasing member to close the secondary throttle.

2. A- charge forming device for an internal combustion engine comprising primary and secondary induction passages, a throttle valve in each of said passages, servo mechanisms for controlling each of said throttles, said primary servo mechanism including meansnorrnally biasing the primary throttle iu an opening direction, an operator adjustable stop opposing the opening movement of the primary throttle, said secondary servo mechanism including means biasingl theV secondary throttle in a closing direction, a conduit communicatingv with said secondary servo for providing athrottle opening force proportional to the quantity ofY air flowthrough said device, valve means associated. with said conduit for reducing said throttle opening force, and anv enginey speed responsive governing mechanism for controlling the primary throttle servo and the valve means to cause the thro'ttles to be moved in a closing direction when enginespeedexceeds a given-value.

3. A chargeforrru'ngl device for'aninternal corn bustiou engine comprising primary and secondary induction passages, a throttle valve in each of said passages, means for opening the primary throttle valve, a first servo mechanism operatively connected to the primary throttle valve, a second servo mechanism operatively connected to the secondary throttle valve, vacuum conduit means communicating the second servo mechanism with the primary induction passage to control the operation of the secondary throttle valve in accordance with the air iiow through the primary induction passage, `a venting mechanism coacting with said vaccum conduit and adapted to admit atmospheric pressure into said conduit, a third servo mechanism operatively connected to the venting mechanism, means normally biasing said third servo mechanism to prevent the admission of atmospheric pressure into said vacuum conduit, a common passage means interconnecting said rst and third servo mechanisms, and a governor device adapted to provide a control pressure proportional to speed, said governor device being operatively interconnected with said common passage means to admit said control pressure to said common passage means to actuate said first and third servo mechanisms and thereby govern the primary and secondary throttle valves.

4. A charge forming device for an internal combustion engine comprising primary and secondary induction passages, a throttle valve in each of said passages, spring means for opening the primary throttle valve, a rst servo mechanism operatively connected to the primary throttle valve, a second servo mechanism operatively connected to the secondary throttle valve, vacuum conduit means communicating the second servo mechanism with the primary induction passage to control the operation of the secondary throttle valve in accordance with the air ow through the primary induction passage, a venting mechanism coating with said vacuum conduit and adapted to admit atmospheric pressure into said conduit, a third servo mechanism operatively connected to the venting mechanism, spring means normally biasing said third servo mechanism to prevent the admission of atmospheric pressure into said vacuum conduit, a common passage means interconnecting said rst and third servo mechanisms, said common passage means being in open communication with a source of manifold vacuum, and a governor device for controlling the pressure level of vacuum in the common passage means in accordance with engine speed, said governor device being adapted to raise the vacuum level in the common passage to overcome the primary throttle, and third servo spring means causing the throttles to move in a closing direction when engine speed exceeds a given value.

5. Carburetor governing-mechanism including primary and secondary induction passages, throttle valves in each of said passages, a servo device for controlling the secondary throttle, a venturi in the primary induction passage, conduit means communicating tfhe venturi and servo whereby the secondary throttle will be opened by a force proportional to the quantity of primary induction passage air ow, means for bleeding atmospheric pressure into said conduit means, and an engine speed responsive governor vfor controlling the bleed means. y

6. A carburetor governing mechanism including primary and secondary induction passages, throttle valves in each of said passages, a servo device for controlling the secondary throttle, a venturi in the primary induction passage, conduit means communicating the venturi and servo whereby the secondary throttle will be opened by a force proportional to the quantity of primary induction passage air flow, means for bleeding atmospheric pressure into said conduit means, and an engine speed responsive governor for controlling the bleed means, said governor being operably connected to said primary throttle valve whereby the throttle valves will be moved in a closing direction when engine speed exceeds a given value.

References Cited in the tile of this patent UNITED STATES PATENTS 2,399,080 Udale Apr. 23, 1946 2,431,816 Mallory Dec. 2, 1947 2,452,698 Strebinger Nov. 2, 1948 2,766,024 Smitley et al. Oct. 9, 1956 2,783,032 Carlson et al. Feb. 26, 1957 

